A woman died after taking a drug used to execute prisoners in the US, a coroner’s court heard today.

Mona Kotecha, 42, of Centurion Building, Queenstown Road, Battersea was found lying cold in her bed by her partner on February 3 this year.

Westminster Coroner’s Court heard that she had been suffering from depression.

She worked as a freelance secretary and had an Open University degree but struggled to find a job which suited her skills.

The day before she died her partner of eight years Trevor Cook left for a conference in Cambridge and said she was behaving normally before he left.

When he returned he found the door of the flat which they shared was locked.

Mr Cook said: "I went into the bedroom to change and found her in bed. She looked so peaceful, I kissed her forehead to wake her up and she was so cold, it was then I dialled 999.

"We had been together for eight years, towards the end she was miserable. In January she seemed to be getting better.

"We had wonderful times together - visited exhibitions, had wonderful holidays. It was unfortunate she could not get a job that suited her abilities and interests."

Medics pronounced her dead at the scene, with police finding no injuries on her body and nothing to suggest she had taken anything.

Four boxes of prescribed anti-depressants were found in the property, but only a few tablets were missing from the containers as she had stopped taking them in January.

A post-mortem report found high levels of a drug in her system which is used to knock-out death-row prisoners before they are executed in the US.

The pathologist said he had never seen anybody die of taking the drug before and said she might have bought it off the internet.

A doctor’s report said she was diagnosed with depression in November 2010 and was given anti-depressants, but made the decision in January to get private counselling and stop taking the tablets.

Coroner Bernard Richmond QC recorded an open verdict as he was unable to determine whether she intended to kill herself by taking the drug because no suicide note was left in the property.

He noted she was Hindu and would have thought carefully about suicide because of her background.

He said: "Mona was a highly intelligent articulate woman who lived at the address with her partner.

"For a Hindu, suicide is something she would have to think very long and hard about, something in that culture to be considered carefully.

"She had not taken it before, and she was not taking her medication. She was not thinking carefully."